The next generation Boeing 747-8 will look a bit different on the inside as reported by this site in Seattle. There will be a skylight, and the option for airlines to install bunks which are located in the ceiling space currently filled with wires and ducts (which are being consolidated and moved to the sides) - this means premium passengers could sit in a regular seat for takeoff and landing, but have a bed for overnight flights - not just a seat that folds down. All the photos are here.
One of the more amusing concepts is the "DreamLav" a more spacious bathroom than the closets currently on board, by using design more cleverly.
However, don't get too excited, it hasn't flown yet and wont till 2009, and only freight versions have been ordered so far. The likelihood that economy class passengers will experience much different beyond the toilet is probably low, as it is first and business class passengers that make most long haul flights profitable (and where the greatest competition on service, comfort is).
Nevertheless, rumour has it that several airlines that serve NZ, including Air NZ, Qantas and Cathay Pacific are interested, given that the mega Airbus A380 is too big for most routes into NZ.